The present invention relates to the field of vehicle devices, and, more particularly, to a tracking and alerting system for a vehicle.
Motor vehicles, such as passenger cars, trucks, busses, fleet vehicles, etc. are widely used and knowing the locations of such vehicles is often desired. For example, should a vehicle be stolen, it would be beneficial to know the vehicle""s location so that authorities could be promptly and accurately directed to retrieve the vehicle. Indeed, the tracking system could plot the getaway path of the thief.
For a company with hired drivers, it may be desirable to know the driver""s whereabouts during the course of the day. Similarly, a rental car agency or other fleet operator, for example, may wish to know the whereabouts of its fleet of vehicles.
It may also be desirable to track the location of a vehicle as it is used throughout the course of a normal day. For parents of younger or older drivers, for example, knowledge of the vehicle""s location may provide some assurance that the driver is at designated locations and following a prescribed route.
A number of patents disclose various systems and approaches to tracking vehicles. For example, U.S. Pat. No. 5,223,844 discloses a tracking system including a control center and a mobile unit installed in the vehicle. The mobile unit may send security warnings to the command center via a wireless transceiver. Position information for the vehicle is determined using a GPS receiver at the vehicle.
U.S. Pat. No. 5,515,043 discloses a similar system which may send one or more preprogrammed telephone messages to a user when away from the vehicle. The user may remotely access location information or cause certain commands to be carried out by entering a personal identification number (PIN).
The widespread availability and use of the Internet has prompted a number of vehicle tracking systems to also make use of the Internet. For example, TelEvoke, Inc. proposed such a system in combination with Clifford Electronics. The system was to provide notification, control and tracking services via the telephone or the Internet. Users could be notified via phone, e-mail, or pager of events such as a car alarm being triggered. Users could control the vehicle remote devices via phone, web, or PDA such as unlocking car doors. Additionally, users could track TelEvoke-enabled vehicles on the Internet or via the telephone. An Internet map could be viewed by the user showing the actual and prior vehicle locations. TelEvoke offered its services via a centralized fully automated Network Operations Center. To reduce the communications costs, it was proposed to use the control channel of the cellular telephone network.
Many conventional tracking units consume relatively large amounts of power when the vehicle is not being operated. Accordingly, such units may quickly discharge the vehicle battery, and theft prevention is thereby lost, for example. Although some tracking units may be equipped with a back-up battery, the back-up battery is typically connected to the load in parallel with the vehicle battery. Although the back-up battery can provide power to the unit in the event the battery cable is cut by a would-be thief, the back-up battery is otherwise drained down in voltage right along with the vehicle battery.
One or more components of the vehicle tracking system may require a higher operating voltage. For example, a cellular telephone transmitter may require a higher operating voltage than other logic or position determining components. These higher operating voltage components are the first to be rendered unavailable as the vehicle and back-up battery voltage drop when the vehicle is unattended. Accordingly, theft prevention capability may be relatively quickly lost when the vehicle is left unattended.
In view of the foregoing background, it is therefore an object of the present invention to provide a vehicle tracking system and associated method that can provide useful features over an extended period when the vehicle is left unattended and the vehicle battery discharges.
This and other objects, features, and advantages in accordance with the present invention are provided by a vehicle tracking system comprising a vehicle tracking unit for a vehicle of a type comprising a vehicle battery, and a monitoring station communicating with the vehicle tracking unit. The vehicle tracking unit preferably includes a vehicle position determining device, a wireless communications device, a back-up battery, and a controller connected to the wireless communications device and the vehicle position determining device. The vehicle position determining device, the wireless communications device and the controller may be considered as defining a power load of the vehicle tracking unit. Moreover, the controller preferably isolates the back-up battery from the power load as a voltage of the vehicle battery drops until reaching a threshold. After or below the threshold the controller causes the back-up battery to selectively power only a first portion of the power load while a second portion of the power load remains powered by the vehicle battery.
The wireless communications device may have a higher operating voltage than the vehicle position determining device. The first portion of the power load that is selectively powered despite the low vehicle battery voltage may be the wireless communications device. In particular, the wireless communications device may be powered for transmission. Accordingly, the back-up battery can be saved for limited communication using the higher voltage wireless communications device and thereby provide useful features even after an extended period during which the vehicle is left unattended and the vehicle battery discharges.
To further conserve power, the controller may reduce operation of the power load as vehicle battery voltage falls. Conversely, the controller may restore operation of the power load based upon the voltage of the vehicle battery rising again, such as upon being recharged.
The controller may further cause transmission of a low vehicle battery voltage alert to the monitoring station based upon the voltage of the vehicle battery falling bellow the threshold. Accordingly, the user may cause the monitoring station to issue a remote start command. The controller may then generate a remote start output to remote start an engine of the vehicle and recharge the vehicle battery based upon the remote start command from the monitoring station.
The vehicle position determining device may comprise a Global Positioning System (GPS) device. In addition, the wireless communications device may comprise a cellular telephone communications device, and, may communicate over a cellular control channel.
Of course, the monitoring station may include a user interface for accepting at least one command from a user and sending at least one alert to the user. The user interface may comprise an Internet interface, and/or a telephone network interface.
A method aspect of the invention is for operating a vehicle tracking unit in a vehicle comprising a vehicle battery. The vehicle tracking unit may comprise a vehicle position determining device, a wireless communications device, and a back-up battery. The method preferably comprises isolating the back-up battery from powering the vehicle position determining device and the wireless communications device as a voltage of the vehicle battery drops until reaching a threshold. After reaching the threshold, the method preferably includes selectively powering the wireless communications device with the back-up battery while the vehicle position determining device remains powered by the vehicle battery.